Variable-speed drive



Jan. 8, 1952 J. Moi-:WAN'

vAikIAsLE-sPEED oiz'ivii 2 SHEETS-SHEET 1 Filed Dec. 9, 1949 INVENTOR.Jawes Alain a1; W 4% Jan. 8, 1952 4.. mas/MN 1 vKRIABLmsPEED Bax-W 2SPEETPSl-EET 2 Filed Dec. 9, 1949 IN V EN TOR. Jamzs Me Eu a/2 PatentedJan. 8, 1952 UNIT ED STATES .PA'TE N T OF FLI CE VARIABLE-SPEED "DRIVEJames McEwan, San Jose,=Cali1'-.

ApplicatlonDecem'ber 9, 1949, Serial No. 1311950 "fllhe "presentinvention relates to v variable speed drives of'a characteradaptedforea-sy use *with various types of equipment, such as-sa'w forautomatic cooling of "the pulleys and the belts associated therewith.

The above. and otherobjects .of the invention are attained in apreferred embodiment of the invention, as illustrated in theaccompanying drawingsjin which: V v

Fig-ure l is a side elevationa'lview of 'a'variable "driveassembly-embodying the invention.

"Figure2is a-plan view of'the rack andlocking pawl of the driveassembly.

"Figure 3' is a sectional view taken as indicated by the line 3-3 inFigure =1 Wibh'lthe belts shown in an extreme adjusted position thereof.

Figure 4 is a side elevational view of one jo'f'the center pulleyelements.

Figure 5 is an inside elevational view of one of the shiftable pulleyelements.

Figure 6 is a side elevational view of a shiftable pulley element.

Figure 7 is an elevational view of a modified form of bracket.

Figure 8 is a sectional view taken as indicated by the line 8-8 inFigure 7.

Referring to Figures 1 and 3 the drive assembly includes a supportingframe III which may be of a character disclosed in my co-pendingapplication, Serial No. 779,001, filed October 10, 1947, for SawSharpener. Mounted on the support or bracket element 10 is a motor IIwhose drive shaft I2 is connected to a pulley I3 around which a V beltI4 is trained. At the opposite end of the support I0 there is provided adriven pulley I6 whose driven shaft II carries a sharpening element suchas a grinding wheel, and this pulley I6 is engaged by a V belt I9.Preferably the pulleys I3, I6, and the belts I4, and I9 are an closed bya guard 2 I.

The respective belts I 4 and I 9 at their inner ends cooperate with twosections of a variable drive structure which will now be described. Thevariable drive structure comprises a center pulley element 22 (Figure 3)of double-faced construction, which is journalled by respective bearingsI3 on a support shaft I4. The shaft I4 is supported in and secured bybolting to a. boss 23 of 3 Claims. (Cl. 74-23017) its an-adjusting lever24 whichis pivoted by "a bolt 26 011- 9. bracket 21. The bracket 21 isprovided Withopposite apertured feet 28 "for "mountingon the supportbracket H) by suitable fastening "screws. 'Cooperatingwiththedouble-faced center pulle'yelement 22 area pair of oppositeshifta'ble pulley element's 3-'I and '32 each of which is slidably'mounted'on a turned end 22a of thecenter element 22. The pulleys '3! and32 are connected *b'ya plurality of throughbo'lts '33 having respect'lvespacers 34 "thereon and extending between the respective pulleys 3| and32 through a er-- tures in the pulleyelement 22 to "insure the properspacing therebetween. As seen in Figures .5 and 6 eachpf'fthe'pulleyelements 3| and 32 are provided with cut-away portions 36 "which provideopenings for introductionof coolingair into "thecenter of thevariable-drive assembly.

It is seen that by movement of the lever '24 about pivot "the centerdistances 1 between the variable drivestructureandthe respective ulleysI3 and F6 will'be changed so that the radial spacing for "the respectivebelts ll and =19 will be varied in o posite directions *to vary thedrive ratioinfa'well-known manner.

In order *to accurately eontm the adjustment of the variable drive andto avoid misalignment of the drive parts due to distortion of theirsupport, the lever 24 is provided with a forked upper end 2411. whichembraces an upper arcuate portion 21a of the bracket 21 with sidesurfaces of the lever and the bracket engaged with each other. On theside of the bracket 21, opposite the lever 24, the forked portions 24aare apertured to receive a stub-shaft 31 which carries an operating knob38 at its upper end. Intermediate the forked portions 24a, there issecured on the stub-shaft 31 a locking pawl 39 which is springurgedcounterclockwise, as viewed in Figure 2, by a spring 4| to engage in aselected one of a series of notches 42 in the top bracket portion 21a.The numerals 2400 through 3600 appearing on the plate 21 in alignmentwith the respective notches 42 indicate the corresponding R. P. M.provided on the output shaft for a given R. P. M. of the input.

Preferably the angle of the face of the pawl 39 with respect to a notch42 in the direction of the high-speed adjustment of the lever 24 (i. e.,.to the left in Figures 1 and 2), is such that the pawl will positivelyprevent such adjustment unless the operating knob 38 is turned todisengage the pawl 39 from a notch 42.

Referring to Figures '7 and 8 there is shown a modified form of bracketconstruction which can be mounted against either of two surfaces atright angles to each other depending upon the desired location of thevariable drive unit. For this purpose the bracket 46 is provided withapertured bosses 41 for engagement against a surface at the side of thevariable drive unit and at its bottom is provided with apertured feet 48for mounting in the manner indicated in Figure 1 in con nection with thebracket 21. The mounting of the variable drive elements and the controllever therefor on the bracket 46 is the same as that shown in Figure 1.

While I have shown and described certain preferred embodiments of theinvention it will be. understood that the invention is capable ofvariation and modification from the form shown so that its scope shouldbe limited only by the scope.

of the claims appended hereto.

I claim: 1. A variable drive unit comprising respective driving anddriven elements; and a variable drive structure connected therebetween,.a support bracket, a control lever mounted for pivoting movement on saidsupport bracket and along one side face of said support'bracket, theother side face of said bracket having a series of notches, a shaftcarried by said lever and projecting through said support bracket andhaving said variable drive structure 'journalled thereon, a spring-.urged pawl pivotally carried by said lever and disposed adjacent saidseries of notches for cooperation therewith, and a handle for operatingsaid pawl to and from engagement with any. selected one of said notches,said support bracket having respective sets of mounting bosses disposedat right angles to each other for selective position- -ingof saidbracket.

latch pawl pivoted in the projecting portions of said forked end, aseries of latching stations on said flange for engagement by said pawl,and a support shaft for said variable drive structure carried by saidcontrol lever.

3. A variable drive unit comprising respective driving and drivenelements and a variable drive structure connected therebetween, a framemember for said drive unit, a support bracket attached to said frame andhaving an arcuate flangeat one end thereof, a control lever pivotallymounted on said bracket about an axis concentric with said flange, andhaving a forked end embracing said flange and projecting beyond theflange, a latch pawl pivoted in the projecting portions of said forkedend, a series of latching notches on said flange each having respectiveside surfaces for engagement by respective surfaces of said pawl, saidpawl and a related latching notch having respective engaged surfaces sodisposed with respect to the direction of movement of said lever toresist withdrawing movement of 2 'said pawl when pressure is appliedthrough said lever and said pawl to said related notch in a direction tocause an increase of speed of the drive unit.

7 JAMES MCEWAN.-

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS .Date

